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fix: max listeners exceeded warning #5227

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Merged
merged 4 commits into from
Oct 1, 2025
Merged

fix: max listeners exceeded warning #5227

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ad5969f
fix: max listeners exceeded warning
kobenguyent Oct 1, 2025
98db0a6
fix: max listeners exceeded warning
kobenguyent Oct 1, 2025
af53c7f
fix: failed types tests
kobenguyent Oct 1, 2025
318fb9c
Update lib/event.js
kobenguyent Oct 1, 2025
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12 changes: 11 additions & 1 deletion lib/event.js
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Original file line number Diff line number Diff line change
Expand Up @@ -2,13 +2,23 @@ const debug = require('debug')('codeceptjs:event')
const events = require('events')
const { error } = require('./output')

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Copilot AI Oct 1, 2025

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The MAX_LISTENERS constant should include a comment explaining why 200 was chosen as the limit and under what conditions this value might need adjustment.

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// The MAX_LISTENERS constant sets the maximum number of event listeners for the dispatcher and process.
// The value 200 was chosen to prevent EventEmitter memory leak warnings in large test suites,
// where many plugins, hooks, or reporters may register listeners. Adjust this value if you encounter
// warnings about possible memory leaks, or if your project requires more listeners due to additional
// extensions or integrations.

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const MAX_LISTENERS = 200

const dispatcher = new events.EventEmitter()

dispatcher.setMaxListeners(50)
dispatcher.setMaxListeners(MAX_LISTENERS)

// Increase process max listeners to prevent warnings for beforeExit and other events
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Copilot AI Oct 1, 2025

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This conditional check and process configuration should include a comment explaining why it's necessary and what specific warnings it prevents.

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// Increase process max listeners to prevent warnings for beforeExit and other events
// Set process max listeners to avoid "MaxListenersExceededWarning" when many listeners are attached to process events (e.g., "beforeExit").
// This is necessary in large test suites to prevent Node.js from emitting warnings about possible memory leaks.

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if (typeof process.setMaxListeners === 'function') {
process.setMaxListeners(MAX_LISTENERS)
}


/**
* @namespace
* @alias event
*/

module.exports = {
/**
* @type {NodeJS.EventEmitter}
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2 changes: 1 addition & 1 deletion package.json
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Expand Up @@ -138,7 +138,7 @@
"@pollyjs/core": "6.0.6",
"@types/chai": "5.2.2",
"@types/inquirer": "9.0.9",
"@types/node": "24.6.0",
"@types/node": "^24.6.0",
"@wdio/sauce-service": "9.12.5",
"@wdio/selenium-standalone-service": "8.15.0",
"@wdio/utils": "9.19.2",
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